Continuity

The vehicle used on the street is not the same vehicle used for close-ups. The first vehicle has a chrome horn ring and plaid seats. The used for close-ups has no horn ring; the seats are a mix of plaid and solid colors.

Factual errors

When Sam first calls his boss Blakely about the case, Blakely says he hopes the insurance beneficiary is the killer because then the company won't have to pay off on the policy. That's incorrect. The company won't pay the killer, but the benefits will be paid to an alternate beneficiary or perhaps to the dead man's estate.